If the pump were operated by a bicyclist and the projectile feed automated I imagine the pneumatic system would win out by a very wide margin regardless of any reduction in overall efficiency.
Once this thing is dialed in, a wind- or stream- rechargeable version is the obvious next step.
I've seen potato guns (obviously much larger bore than this) and inflated bicycle tires to 100psi+
How do you imagine making the cycle time better "by a very wide margin" compared to lifting 100 pounds less than 10 feet?